饲料中n-3高度不饱和脂肪酸含量对花尾胡椒鲷亲鱼组织的脂质含量和脂肪酸构成的影响

Effects of Dietary n-3 HUFA Levels on Lipid Content and Fatty Acid Composition in Tissues of Plectorhynchus cinctus Broodstock

以n-3高度不饱和脂肪酸(n-3 HUFA)含量(w)为1.12%、2.40%、3.70%、5.85%的4种配合饲料或冰鲜杂鱼喂养花尾胡椒鲷Plectorhynchus cinctus雌亲鱼1周年,研究饲料中n-3 HUFA含量对性腺、肌肉和肝胰脏等组织的脂质含量和脂肪酸构成的影响.结果显示,各组织中的脂质含量在各投喂组之间无显著差异(P>0.05).然而,在1.12%、2.40%和3.70%(w)投喂组,其性腺和肌肉脂质中18∶2n-6、二十碳五烯酸(EPA)、n-3多不饱和脂肪酸(n-3 PUFA)、n-3 HUFA的含量与饲料中相应脂肪酸的含量存在较明显的平行变化趋势;在性腺脂质中,1.12%、2.40%、5.85%(w)投喂组的二十二碳六烯酸(DHA)和1.12%(w)投喂组的n-3 PUFA、n-3 HUFA的含量都显著低于冰鲜杂鱼投喂组(P<0.05);在1.12%、2.40%和3.70%(w)投喂组,上述3种组织中的n-3 PUFA、n-3 HUFA、DHA含量以及DHA/EPA比值都显著高于饲料中相应脂肪酸的含量和比值(P<0.05).结果表明,花尾胡椒鲷组织中的脂肪酸构成受饲料中n-3 HUFA含量影响,受影响的顺序是性腺>肌肉>肝胰脏;组织对n-3 PUFA、特别是DHA具有较强的选择性保留作用,说明这些脂肪酸在性腺发育成熟中具有重要的生理作用.

The effects of dietary n-3 highly unsaturated fatty acid （ n-3 HUFA） content on the lipid content and fatty acid composition in gonad, muscle and hepatopancreas of broodstocks were investigated in Plectorhynchus clnctus. Broodstocks were fed trash fish and four formulated diets with 1.12%, 2. 40%, 3.70% or 5. 85% of n-3 HUFA, respectively, through their reproductive cycle. The lipid content in each tissue showed no significant difference among groups （P 〉0. 05）. However, the contents of 18： 2n-6, EPA, n-3 PUFA and n-3 HUFA in the lipid of gonad and muscle of fish fed 1.12% -3.70% n-3 HUFA diets were directly influenced by dietary n-3 HUFA levels and exhibited parallel change pattern with the respective dietary levels. In the lipid of gonad, the contents of n-3 PUFA and n-3 HUFA in fish fed 1.12% n-3 HUFA diet, and DHA in fish fed 1.12%, 2. 40% and 5.85% n-3 HUFA diets were significandy lower than those in the trash fish group （ P 〈 0. 05）. The contents of n-3 PUFA, n-3 HUFA and DHA, and the DHA/EPA ratio in all the mentioned tissues of fish fed 1.12% -3.70% n-3 HUFA diets were obviously higher than the respective dietary levels （ P 〈0. 05 ）. The results showed that the fatty acid composition in tissues of female P. cinctus broodstocks could be affected, with the order of gonad 〉 muscle 〉 hepatopancreas, by dietary n-3 HUFA levels. The preferentially retaining of n-3 HUFA, particularly of DHA in the tissues suggests their physiological importance in the gonadal development and maturation.